Archive image from page 509 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana0401todd Year: 1847 488 SEMEN. Spermatozoon, of Phalluria monacha. (AfierKolliker.) Tunicata.—Among the Tunicata the Ascidia possess spermatozoa quite similar to those of the Lamellibranchi- Fig. 365. ates, having a dis- tinct head of dif- erent shape and a slender tail. The size of the sperma- tozoa is, however, usually rather larger (fig. 365.); the head is usually ji'' — i-s', the tail fluctu- ating between gV —i,V'' The sper- matozoa seem to want a body in the Salpae, accor
Archive image from page 509 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana0401todd Year: 1847 488 SEMEN. Spermatozoon, of Phalluria monacha. (AfierKolliker.) Tunicata.—Among the Tunicata the Ascidia possess spermatozoa quite similar to those of the Lamellibranchi- Fig. 365. ates, having a dis- tinct head of dif- erent shape and a slender tail. The size of the sperma- tozoa is, however, usually rather larger (fig. 365.); the head is usually ji'' — i-s', the tail fluctu- ating between gV —i,V'' The sper- matozoa seem to want a body in the Salpae, according to the observations of KoUtker. The endogenous formation of the spermatozoa in the Ascidia is as little distinct as among the Lamellibranchiata. It seems, also, with regard to the former, that the developing vesicles simply extend themselves into the spermatozoa. At a previous stage of deve- lopement, these vesicles are, however, con- tained (either singly or in a greater number) in the interior of cells. ARTICULATA.—In the second great division of the Invertebrate animals, among the Artliro- pocla, the filiform shape of the spermatozoa, if indeed it occurs at all, is generally still more marked in its developement than in the Mollusca. The spermatozoa are long and slender fibres, which, perhaps in all cases, are deficient of a real, distinct, and separate body, being at the utmost only slightly enlarged at the anterior end. The spermatozoa of some few groups, however, differ from this, and ex- hibit so striking a form and arrangement that one can hardly at first recognise in them the genuine spermatic elements. The question, indeed, arises, whether these parts are really in all cases the developed spermatozoa, or whether they do not constitute mere stages of developement. We shall subsequently return to this question ; let the remark suffice for the present, that in some cases the circumstances observed seem to favour the latter hypothesis. Insecta.—The sperma
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